CD40 发夹siRNA真核表达载体构建及其对CA46细胞CD40表达的影响

目的: 构建人类CD40膜蛋白siRNA的真核表达载体, 观察其对CA46细胞上CD40表达、细胞增殖能力和凋亡的影响。方法: 合成两条编码发夹siRNA序列的单链DNA,并将其克隆到pSilenCircle载体中, 构建含目的基因片段的重组质粒siCD40 /pSilenCircle。以同样的方法, 分别构建相对应的编码反义RNA及无关基因的重组质粒antiCD40 /pSilenCir cle和siFly/pSilenCircle。以上述重组质粒分别瞬时转染CA46细胞后, 用流式细胞仪检测CA46细胞上CD40的表达和细胞凋亡情况, 用MTS法(改良的MTT法)测定细胞的增殖能力。结果: ①成功地构建了两个CD40发夹siRNA的真核表达载体siCD40 /pSilenCircle、两个相对应的反义RNA真核表达载体antiCD40 /pSilenCircle和无关基因重组质粒siFly/pSilenCir cle。②与siFly/pSilenCircle转染组相比较, siCD40 /pSilenCir cle转染组和antiCD40 /pSilenCircle转染组CA46细胞上CD40的表达均明显减少, 但细胞的增殖能力和凋亡未发现明显变化。结论: 构建的两个CD40发夹siRNA的真核表达载体siCD40 /pSilenCircle, 可有效地抑制CA46细胞上CD40分子的表达, 但不影响细胞的增殖和凋亡。RNA干扰技术可望作为一种有效地调控基因功能的方法。     

LMP1促鼻咽癌细胞生长与端粒酶活性

为探讨EB病毒潜伏膜蛋白 1(LMP1)促鼻咽癌细胞生长作用与端粒酶活性的关系 ,用LMP1基因真核表达质粒转染鼻咽癌CNE1细胞 ;脂质体介导端粒酶反义核酸处理转染细胞 ;MTT法检测细胞增殖能力 ;原位杂交法检测端粒酶逆转录酶 (hTERT)mRNA表达 ;免疫组化法检测LMP1蛋白表达。结果显示 :转染LMP1基因的细胞增殖能力和hTERTmRNA表达水平均显著高于未转染和转染空载质粒的细胞 (均P <0 0 1)。经端粒酶反义核酸作用 4 8h ,LMP1基因转染细胞的细胞增殖能力、hTERTmRNA和LMP1蛋白表达水平均显著低于空白对照组 (均P <0 0 1) ,反义核酸和脂质体处理组上述各指标无显著变化 ;反义核酸组LMP1基因转染细胞的增殖能力和hTERTmRNA表达水平仍均显著高于未转染细胞和转染空载质粒的细胞 (均P <0 0 1)。以上结果提示 :EB病毒LMP1的促鼻咽癌细胞生长作用与端粒酶活性密切相关。     

人CD40-IgG1Fc段融合蛋白对EBV转化的B细胞凋亡的影响

目的 探讨人CD40-IgG1Fc段融合蛋白对EB病毒(EBV)转化的B淋巴细胞在细胞生长及凋亡方面的影响.方法 应用流式细胞术检测EBV转化的B淋巴细胞膜表面异位表达CD40L;应用本研究所构建的CD40-IgG1Fc段融合蛋白CHO稳定表达株的培养上清与EBV转化的B淋巴细胞共孵育,通过MTT法检测B细胞的生长变化,吖啶橙(AO)、溴化乙锭(EB)双染色法和DNA ladder法检测融合蛋白对B细胞凋亡的影响.结果 EBV转化的B细胞膜表面异位表达CD40L;CD40IgG1Fc段融合蛋白可有效抑制EB病毒转化的B细胞生长,抑制程度与蛋白浓度呈正相关;AO与EB双染色法及DNA ladder法均检测到B细胞凋亡明显增加,与共孵育时间呈正相关.结论 CD40-CD40L的相互作用是EBV转化的B细胞异常激活的重要机制,人CD40-IgG1Fc段融合蛋白能阻断CD40-CD40L的相互作用,抑制EB病毒转化的B细胞的生长,促进其凋亡,为下一步自身免疫性疾病的临床实验治疗奠定了基础.     

表达载体介导的反义RNA抑制人巨噬细胞移动抑制因子的表达

目的：研究表达载体介导的反义RNA对人巨噬细胞移动抑制因子(MIF)表达的抑制作用。 方法:用亚克隆技术构建可转录MIF反义RNA的真核表达载体pcDNA3-antiMIF。用lipofectamine2000分别将pcDNA3、pcDNA3-antiMIF转染可表达MIF的HEK293(293-MIF)细胞，用Real-time定量PCR鉴定MIF mRNA表达水平。将pcDNA3-antiMIF转化人脐静脉血管内皮细胞(HUVECs)，建立可表达MIF反义RNA的HUVECs(HUVECs-antiMIF)细胞。将MIF的真核表达载体pSecTag-MIF转染HUVECs-antiMIF，用Real-time定量PCR鉴定MIF mRNA的表达水平。 结果:正确构建了MIF反义RNA的表达载体pcDNA3-antiMIF。MIF 反义RNA对293-MIF细胞中MIF表达的抑制水平达32%（P<0.05）。建立稳定表达MIF反义RNA的HUVECs-antiMIF细胞株。HUVECs-antiMIF中MIF的表达受到抑制，表达水平降低40%（P<0.05）。 结论:表达载体介导的反义RNA能有效地抑制MIF的表达，建立了稳定表达MIF反义RNA的HUVECs。     

EB病毒潜伏膜蛋白1对鼻咽癌细胞P53蛋白表达的影响

目的:研究EB病毒潜伏膜蛋白1(LMP1)对鼻咽癌细胞P53蛋白表达的影响。方法:将LMP1基因真核表达质粒转染至鼻咽癌CNE1细胞,脂质体介导端粒酶反义核酸处理转染细胞,MTT法检测细胞增殖能力,免疫组化法检测LMP1和P53蛋白表达,原位杂交技术检测端粒酶逆转录酶(hTERT)mRNA表达。 结果:对照组,转染并表达LMP1基因的细胞的增殖能力、P53蛋白和hTERT mRNA表达水平均显著高于未转染细胞和转染空载质粒的细胞。端粒酶反义核酸作用组,LMP1基因转染细胞的LMP1蛋白表达水平显著低于对照组(P＜0.01);LMP1基因转染细胞与未转染细胞和转染空载质粒的细胞的增殖能力、P53蛋白和hTERT mRNA表达水平均显著低于对照组(P＜0.01),但LMP1基因转染细胞的增殖能力和P53蛋白表达水平仍显著高于未转染细胞和转染空载质粒的细胞(P＜0.01)。 结论:EB病毒LMP1可促进鼻咽癌细胞P53蛋白的表达。     

反义RNA阻断Hep G2细胞FasL的表达及功能研究

应用分子克隆技术将人FasLcDNA片段反向插入逆转录病毒载体pLXSN ,构建重组质粒pL (hFasL AS )SN ,转染包装细胞PA317后获得FasL反义RNA重组逆转录病毒表达载体假病毒上清 ,经NIH3T3细胞检测其感染滴度后转染肝癌细胞株HepG2细胞并筛选建系 ,命名为HepG2 hFasL AS。半定量RT PCR检测显示HepG2 FasL AS细胞FasL的mRNA明显少于正常HepG2细胞 ;FACS检测显示HepG2 FasL AS细胞FasL的表达与HepG2细胞相比显著下降 ;同时 ,HepG2 FasL AS细胞导致HL 6 0细胞凋亡能力有所下降。表明人FasL反义RNA重组逆转录病毒表达载体能抑制转染细胞FasL的表达并下调其致凋亡功能     

CIITA反义RNA抑制MHCII类分子表达

为探索利用CIITA (MHCclassIItransactivator)基因反义RNA抑制MHCII类分子表达的可能性 ,为CIITA的应用研究奠定基础。利用RT PCR扩增能与CIITAcDNA第 95至 5 0 0bp互补的片段 ,并构建成pcDNA3/CIITAa 重组质粒 ,脂质体转染法将其转入人HeLa/Raji细胞和猪PIEC/L2 3细胞 ,流式细胞术动态检测反义RNA对人 /猪MHCII类分子的抑制率和抑制程度。结果显示HeLa、Raji、PIEC和L2 3四种细胞MHCII类分子受抑制率分别为 4 6 7% ( 7/ 15 ) ,4 0 % ( 6 / 15 ) ,4 6 7% ( 7/ 15 )和33 3% ( 5 / 15 )。典型受抑克隆细胞MHCII类分子受抑程度高达 85 % ,反义RNA对MHCII类分子的抑制时间持续 35～ 5 0d。CIITA反义RNA能有效抑制人 /猪MHCII类分子的表达 ,它在自身免疫和移植免疫中有一定的应用前景     

慢病毒介导RNA抑制黑素瘤细胞Foxp3蛋白表达

目的:利用RNA干扰(RNAi)技术在体外干扰小鼠B16黑素瘤细胞Foxp3基因表达,探讨RNA干扰用于黑素瘤治疗的可行性。方法:针对Foxp3基因设计小干扰RNA(siR-NA),构建起短发夹状RNA(shRNA)慢病毒表达载体,并转染小鼠B16细胞,在体外诱导RNA干扰。分别采用Westernblot和RT-PCR检测Foxp3基因的表达情况;ELISA检测TGF-β1、TGF-β2和IL-10等细胞因子的变化;将干扰后的小鼠B16细胞与CD4+CD25-T淋巴细胞共培养,CCK8法检测CD4+CD25-T淋巴细胞增殖能力。结果:通过Foxp3 shRNA的转染,可实现对B16细胞Foxp3表达的沉默,可下调肿瘤细胞对CD4+CD25-T淋巴细胞增殖抑制的能力,并且下调TGF-β1、TGF-β2和IL-10等细胞因子的表达,尤其是TGF-β2的表达。结论:RNA干扰可抑制小鼠黑素瘤细胞靶基因Foxp3的表达及细胞增殖,并对CD4+CD25-T淋巴细胞增殖抑制的能力减弱,同时减弱抑制性细胞因子的分泌,为黑素瘤的基因治疗提供了新思路。     

CD46 RNAi对CD59介导的T细胞信号转导的作用研究

目的构建携带针对CD46基因的pSUPER retro RNAi逆转录病毒载体,研究糖基磷脂酰肌醇(GPI)锚定蛋白CD59与CD46在介导T细胞信号转导中的相关性。方法将能转录产生靶向CD46小发夹RNA(shRNA)的寡核苷酸序列,克隆入逆转录病毒载体pSUPER retro,转化大肠杆菌JM109并转染Jurkat细胞。将Jurkat细胞分为未转染的Jurkat细胞组(Ⅰ组)、转染空质粒的Jurkat细胞组(Ⅱ组)、转染CD59干扰质粒的Jurkat细胞组(Ⅲ组)及转染CD46干扰质粒的Jurkat细胞组(Ⅳ组)。用RT-PCR、Western blot技术检测各组细胞中的CD59、CD46基因的表达水平。用噻唑蓝(MTT)比色法检测CD46与CD59联合作用对4组Jurkat细胞的增殖效应。结果重组载体经PCR及限制性内切酶酶切鉴定初步成功后送测序,结果表明序列正确,构建成功,稳定转染后,Ⅳ组细胞CD46分子的表达被成功抑制,Ⅲ组细胞CD59分子的表达被抑制。Ⅰ组和Ⅱ组细胞CD46与CD59单抗联合作用后,增殖能力明显高于Ⅲ组、Ⅳ组(P<0.05);但Ⅰ组和Ⅱ组,Ⅲ组和Ⅳ组之间无差异。结论 CD59可增强CD46对T细胞信号转导的效应。     

重组质粒pcDNA3.1-IL-15转染对小鼠骨髓DC上表面分子的表达及功能的影响

目的: 探讨重组质粒pcDNA3. 1 IL- 15对小鼠骨髓树突状细胞(DC)表面共刺激分子的表达及免疫功能的影响。方法: 构建真核表达质粒pcDNA3. 1 IL- 15, 以其转染小鼠骨髓DC。用流式细胞仪检测转染的DC表面CD40、CD80及CD86的表达, 并分析转染的DC刺激脾淋巴细胞中CD4 、CD8 T细胞亚群的变化。用MTT比色法检测转染的DC刺激T细胞增殖的作用。用ELISA法检测T细胞产生IFN- γ的水平。结果: pcDNA3. 1- IL- 15转染的DC表面CD40、CD80及CD86的表达均有不同程度的升高。重组质粒转染的DC可诱导小鼠脾淋巴细胞中CD4 、CD8 T细胞增殖, 但CD4 /CD8 T细胞的比值降低。结论: 重组质粒pcDNA3. 1 -IL- 15转染可提高DC表面共刺激分子的表达并增强其免疫功能。     

小鼠OX40稳定表达细胞株的构建及其对B细胞促分化作用的研究

目的:构建稳定表达小鼠OX40的细胞株HUVEC,并探讨其对B细胞的促增殖作用。方法:从ConA活化的小鼠胸腺淋巴细胞中提取总RNA,应用RT-PCR法扩增小鼠OX40的cDNA,并将其克隆到pUCm-T载体中,经PCR、酶切和测序分析,进而构建pIRES2-EGFP-OX40重组真核表达载体。以脂质体法转染HUVEC,经G418筛选后,用流式细胞术检测OX40分子的表达。采用3H-TdR掺入法,研究OX40信号对体外培养的B细胞的促分化作用。结果:构建了OX40基因的真核表达载体。经PCR、酶切和测序证实,插入的目的片段与GenBank登录的小鼠OX40cDNA序列完全一致。用G418筛选后,获得能稳定表达小鼠OX40蛋白的HUVEC细胞。3H-TdR掺入法结果显示,小鼠OX40稳定表达的细胞HUVEC对体外培养的B细胞具有促增殖、分化的作用。OX40/OX40L信号与CD40/CD40L信号具有协同作用。结论:成功地构建小鼠OX40稳定表达地细胞,OX40对B细胞具有促增殖、分化作用。     

Enforced and prolonged CD40 ligand expression triggers autoantibody production in vivo.

CD40, a glycoprotein expressed on B lymphocytes plays an important role in B cell development, growth and differentiation. The ligand for the CD40 is a 39-kDa glycoprotein (CD154) expressed on the surface of activated T lymphocytes and is essential for thymus-dependent humoral immunity. The expression of CD154 is tightly regulated and its transient expression reduces the chances of potentially deleterious bystander activation of B cells. Stimulation through CD40 has been studied in vitro by using antibodies against CD40, by membranes of activated T cells or lately, by CD154 transfected cells. In this work we have evaluated the outcome of CD40-CD40 ligand interaction in vitro and in vivo by using CD154-transfected L929 cells. In vitro assays showed that CD154-L929 cells can induce on B cells: IL-4-dependent proliferation, up-regulation of CD23, CD54 and class II molecules and can also rescue WEHI-231 B cell lymphoma from anti-IgM-induced apoptosis. Interestingly, in vivo assays revealed that when CD154-L929 cells were inoculated into the spleen, mice developed a strong but transient production of anti-erythrocyte autoantibodies. Through B lymphocyte activation with CD154-transfected L929 cells both in vitro and in vivo, our data reveal that enforced and prolonged expression of CD40 ligand overcomes the tightly regulated mechanisms of B cell activation, triggering the production of autoantibodies. This system might be used to evaluate the early steps of an autoimmune response and the role of CD40-CD154 in the induction of primary responses in vivo.     

Establishment and Characterization of a Human T-Lymphocyte Cell Line Immortalized by SV40 and with Abnormal Expression of TCR/CD3

Human lymphocytes derived from the peripheral blood of a healthy woman were transfected with a plasmid carrying the simian virus 40 (SV40) large T antigen. The successfully transformed cells contained SV40 large T DNA and were negative for Epstein–Barr virus (EBV) and human T-cell leukaemia virus (HTLV)-1 genomes. The immortalized cell line was assigned to the T-lymphocyte lineage on the basis of morphological, immunological and cytochemical criteria. While the cells expressed CD1a and CD4 at the cell surface, the CD3 complex was solely intracytoplasmic. Immunoprecipitation studies indicated that these cells lacked T-cell receptor (TCR) α-chains but not β-chains. They were negative for activation markers such as CD25, CD69 and major histocompatibility (MHC) class II molecules. In addition, the transformed cells exhibited a complete growth independency towards interleukin-2 (IL-2). However, after phorbol ester stimulation, CD25 and CD69 markers were expressed and IL-2 was secreted. This new human immortalized T-lymphocytic cell line, which is cell-surface TCR/CD3-negative, may be useful as an in vitro model for studying TCR/CD3 assembly, expression and signal transduction.     

mCD1.1分子的真核表达及其对NKT细胞的刺激作用

目的:获得稳定表达mCD1.1分子的细胞系,研究其对肝脏和肠系膜淋巴结淋巴细胞的刺激作用。方法:分离C57小鼠的小肠上皮细胞,制备总RNA,通过RTPCR扩增mCD1.1编码区基因,将其克隆至真核表达载体pcDNA3.1。将所得重组质粒pcDNA3.1mCD1.1通过电穿孔法转至CHO细胞中,在含G418的的选择性培养基中筛选抗性克隆,利用RTPCR和流式细胞术对挑取的克隆进行mCD1.1表达的鉴定。将表达mCD1.1的细胞与新分离的肝脏和肠系膜淋巴结(MLN)的淋巴细胞进行共培养,并用丝裂霉素C抑制CHO细胞的增殖,然后利用MTT法检测淋巴细胞的增殖情况;另外将表达mCD1.1的CHO细胞与淋巴细胞共培养后,分离淋巴细胞,然后用PEantiNK1.1和CychromeantiCD3对其进行标记,利用流式细胞术检测CD3细胞中NK1.1阳性细胞的比例。结果:通过RTPCR,得到mCD1.1的编码区基因,序列与预期相符;通过多次鉴定,证明筛选得到的细胞克隆可稳定表达mCD1.1;CHOmCD1.1细胞与新分离的淋巴细胞共培养,在有无LPS存在的情况下,均能刺激淋巴细胞发生增殖,并使CD3 细胞中NK1.1阳性细胞的比例增加。结论:表达mCD1.1的CHO细胞能够刺激NKT细胞增殖。     

Human dendritic cells activate T lymphocytes via a CD40: CD40 ligand-dependent pathway

The CD40: CD40 ligand (CD40L) interaction provides T lymphocyte-mediated help for B lymphocyte and monocyte function but has also been shown to serve as a co-stimulus for T lymphocyte activation. In this report, we studied the regulation of CD40 expression and its functional relevance for the human dendritic cell (DC) stimulation of T lymphocytes. Only a small subpopulation of directly isolated blood DC expressed CD40. However, CD40 was rapidly up-regulated by culture, and its expression was further enhanced by interleukin (IL)-1α, IL-1β, IL-3, tumor necrosis factor-α and granulocyte/macrophage-colony-stimulating factor. Expression of CD40L on DC was not detected. The proliferation of T lymphocytes in an allogeneic mixed leukocyte reaction, stimulated by blood DC or epidermal Langerhans cells, was significantly reduced in the presence of the CD40 immunoglobulin (CD40Ig) fusion protein or CD40L monoclonal antibodies. Cross-linking of CD40 on directly isolated DC with mouse CD40L trimer (mCD40LT) markedly augmented CD80 and CD86 up-regulation. Nevertheless, the same cross-linking mCD40LT inhibited DC stimulated T lymphocyte proliferation. When CD40Ig was added simultaneously with CTLA-4Ig, only minimal and variable additional inhibition of DC-stimulated allogeneic T lymphocyte proliferation and IL-2 secretion was observed, compared to each fusion protein alone. These results suggest that both CD80/CD86-dependent and -independent components of DC-T lymphocyte CD40: CD40L co-stimulation exist and further emphasize that the majority of blood DC have to differentiate or be activated to express co-stimulatory molecules.